Add a comment for ignoring spring-boot-3 for now (#2894)

Author: heyams

.github/dependabot.yml

@@ -29,6 +29,10 @@ updates:
       - dependency-name: "com.squareup.moshi:*"
         # 1.12.0 and above use okio 2.x which pulls in kotlin libs (which are large)
         versions: [ "[1.12,)" ]
+      - dependency-name: "org.springframework.boot:spring-boot-gradle-plugin"
+        # this is used for smoke tests
+        # spring boot 3 requires Java 17, and we're not ready yet
+        versions: [ "[3,)" ]
       - dependency-name: "javax.servlet:javax.servlet-api"
         # applicationinsights-web (classic sdk) is intentionally compiled and against Servlet 3.0
         versions: [ "[3.1,)" ]